374 



PSEUDOTUBERCULOSIS AND ACID-FAST BACILLI 



FIG. 153 



in the dysenteric discharges and in the mucosa particularly of the 

 small intestines. The disease was first recognized as one of a peculiar 

 type by Johne and Frothingham in 1895. They found the acid-fast 

 bacillus, and were at first inclined to look upon it as an avian tubercle 

 bacillus. Other cases were then reported in Europe by Markus, 

 Lienan and Van den Eeckhout, Borgeaut, and Bang. The first cases 

 in the United States were noticed by Pearson in Pennsylvania and by 

 Beebe in Minnesota. Since then not a few 

 cases have been observed in this country. 

 The author received material from a case in 

 1908 through the kindness of Professor Alex- 

 ander, of Madison, Wis., and a second case 

 likewise from Wisconsin, through Dr. Hermann 

 Schwarze. 



Pathologic Lesions. Animals dead from 

 chronic bacterial dysentery upon postmortem 

 examination are generally found to be very 

 much emaciated and extremely anemic. There 

 are otherwise no marked changes in the in- 

 ternal organs except in the intestines, which 

 are the seat of characteristic lesions. The 

 small intestine in particular shows great thick- 

 ening. If, however, the disease has been 

 recognized early by microscopic examination 

 and inoculations and the animal has been 

 slaughtered while still in good condition the 

 thickening may be moderate; but if death has 

 occurred both the mucosa and the submucosa 

 of the small intestine are much thickened. 

 The former develops coarse, very prominent 

 corrugations, which show a congested and 

 sometimes even hemorrhagic surface. These 

 changes may extend from the small to the 

 large intestines. Microscopic examination of 

 sections of the mucosa of the small intestine 

 shows that the thickening is due chiefly to the 

 increase in fixed connective-tissue cells and to 

 infiltration by an edematous exudate. There 

 are neither true tubercles nor giant cells, but 

 between the cells enormous numbers of acid- 

 fast bacilli are encountered. These are much 

 more numerous than in any form of tuberculosis, including avian 

 tuberculosis. There is a striking similarity in morphology, numbers, 

 and grouping between the acid-fast bacilli of this bovine chronic 

 dysentery and the bacilli of human lepra. 



Morphology. The bacillus of chronic dysentery of cattle is a rod 

 2 to 3 micra long and 0.5 micron wide. It presents itself in regular 



The small intestine of a 

 cow in chronic bacillary 

 dysentery. (Johne's dis- 

 ease.) 



